The present invention relates to fluorochemical compositions for the treatment of substrates, in particular fibrous substrates such as textile to impart stain release properties to those substrates.
Certain fluorochemical compositions have been used to impart various properties, such as water and/or oil repellency, waterproofness, stain release and anti-staining to various substrates like leather, textiles and paper. For example, U.S. Pat. No. 4,563,493 describes the use of certain omega-perfluoroalkyl-1,2-epoxy-alkane copolymers as water and oil repellent treatments.
U.S. Pat. No. 4,399,077 discloses the use of certain polyoxy perfluorinated surface active oligomers in cosmetic compositions for hair to slow down the flow of sebum and the rate at which hair becomes greasy again.
EP 331307 discloses certain perfluoroalkyl polyether glycols derived from 3-perfluoroalkyl-1,2-epoxy propane. It is stated that these polyether glycols are useful for making polyurethanes in a condensation reaction with a di- or polyisocyanate.
U.S. Pat. No. 4,540,765 discloses certain fluorochemical polyurethanes that it alleges impart permanent oil and/or water repellency to inorganic and organic objects. The polyurethanes disclosed in this patent are obtained by a condensation of a fluorochemical diol and a di- or polyisocyanate.
Certain fluorochemical compositions are also used to facilitate stain release from substrates such as fabrics. Such compositions may also include various modifying additives such as softeners, stiffeners and lubricants which are added to the composition to impart desired properties to a fabric. These additives typically increase the oleophilicity of the fabric, thereby significantly increasing the fabric""s tendency to accept oily stains and reducing its ability to release such stains after laundering.
An improvement to such compositions are fluorochemical treatments consisting of certain fluorinated compound and a non-fluorinated hydrophilic compound mixtures as well as treatments containing certain xe2x80x9cchemical hybridxe2x80x9d fluorochemical compounds which contain fluorochemical oleophobic segments (xe2x80x9cFxe2x80x9d) and non-fluorinated hydrophilic segments (xe2x80x9cHxe2x80x9d). Such improvement treatments are known to act as stain release compositions since they provide oil repellency during normal wear and inhibit wicking or diffusion of oily soils into the fabric or fiber bundles and facilitate soil release during laundering.
U.S. Pat. No. 3,574,791 discloses certain block-copolymers consisting of F and H segments and alleges that such polymers are useful as stain-release agents. The xe2x80x9cFxe2x80x9d segments are substantially free of hydrophilic groups whereas the xe2x80x9cHxe2x80x9d segments are substantially free of fluorinated aliphatic groups. The patent teaches that this segmentation of the polymer renders it xe2x80x9cautoadaptablexe2x80x9d, i.e., a fabric treated with the polymer will perform as an oil and water repellent in an atmospheric environment and will become hydrophilic when laundered thereby facilitating stain removal. The patent contemplates various chemical linkages for connecting the xe2x80x9cFxe2x80x9d and xe2x80x9cHxe2x80x9d segments, and amongst them is a urethane linkage derived from the reaction of an alcohol and an isocyanate.
U.S. Pat. No. 4,046,944 discloses certain fluorochemical compositions containing block-copolymers that contain a fluorinated polyurethane segment linked to a hydrophilic polyethyleneoxide block via a urea linkage. The patent teaches that the fluorochemical composition can be used to impart stain release properties to a fabric.
U.S. Pat. No. 5,841,027 discloses certain fluorocarbamate soil-release agents. The urea linkage-containing alkoxypolyoxyalkylene fluorocarbamates are prepared by reacting (a) at least one polyisocyanate containing at least three isocyanate groups, with (b) at least one fluorochemical reagent containing one functional group having at least one hydrogen atom and at least two carbon atoms each of which is substituted with at least two fluorine atoms, (c) at least one hydrophilic, water-solvatable reagent containing a single functional group having at least one reactive hydrogen atom, and (d) at least one reagent containing one reactive hydrogen atom and, which on reaction with an isocyanate group, yields functionality which has abeyant chemical reactivity with fibrous substrates and then reacting the product with water. The patent discloses that reactants (b), (c) and (d) react with 55% to 95% of the isocyanate groups, and water reacts with the remainder.
JP-A-08-225493 discloses certain polymers derived from fluorine containing monomers and alleges such polymers are useful as stain releasing water and oil repellents. The monomers are fluorochemical acrylates or methacrylates that are prepared by first reacting, e.g., an alkyl ether of a polyglycol with a perfluoroalkyl epoxypropane and subsequently reacting the obtained alcohol with (meth)acryloyl chloride to obtain the fluorochemical monomer.
Despite the many fluorochemical compositions taught by the art to impart stain release properties to a substrate, there continues to be a desire for new fluorochemical compositions with improved properties. Properties like easy cleanability of natural fiber-based substrates (e.g., cotton and blends of cotton and polyester) are desired. In particular, it is especially desired to have treatments that will permit the easy removal of oil-type stains (like dirty motor oil and vegetable oil) and water-based stains (like tea and coffee) from such substrates. Also desired are fluorochemical compositions having low manufacturing cost, high storage stability, easy emulsifiability and high performance even if applied in low concentrations.
The present invention provides a method of treating of a substrate comprising the step of contacting the substrate with a fluorochemical composition which comprises a condensation product of a di- or tri-isocyanate and at least one polyether. The polyether being obtainable by reacting a fluorochemical substituted epoxide according to formula (I) with a compound of formula (II) or formula (III): xe2x80x83HX1xe2x80x94Bxe2x80x94X2Hxe2x80x83xe2x80x83(II)
(Rfxe2x80x2)kxe2x80x94L2xe2x80x94X2Hxe2x80x83xe2x80x83(III)
wherein:
B represents an organic residue obtained by removing the groups HX1 and HX2 from the compound in formula (II);
X1 and X2 are each independently selected from the group consisting of O, NH and S;
L1 represents an organic divalent linking group;
L2 represents an organic linking group having a valence of k+1;
k is an integer of 1 to 10;
Rf and Rfxe2x80x2 are each independently selected from the group consisting of perfluorinated and partially fluorinated aliphatic groups;
s is 0 or 1, and
a is 0 or 1, and preferably is 1.
Substrates treated in accordance with the invention have good stain release properties, particularly to oil stains or tea stains, so stains can be more easily removed from the treated substrate in a laundering procedure.
In another aspect, the invention provides certain fluorochemical compositions for use in the method, a process for the preparation of the fluorochemical compositions and the polyether used to prepare the fluorochemical compositions.
The condensation product used in the fluorochemical composition is prepared by reacting a di- or tri-isocyanate with certain polyether obtainable by reacting a fluorochemical substituted epoxide of formula (I) with a compound of according to formula (II) or (III). Mixtures of compounds of formula (I), (II) or (III) may also be used to practice the invention.
The molar ratio of the fluorochemical substituted epoxide to the compound according to formula (II) is preferably between about 2 and 50 and more preferably between about 5 and 20. The molar ratio of the fluorochemical substituted epoxide to the compound according to formula (III) is preferably between about 2 and 30 and more preferably between about 4 and 15. Preferably, the molecular weight of the polyethers obtainable from a reaction of a compound of formula (I) with a compound of formula (II) is between about 2,000 and 50,000 g/mol, more preferably is between about 6,000 g/mol and 15,000 g/mol. The molecular weight of polyethers obtainable by reaction of a compound of formula (I) with a compound of formula (III) is preferably between about 3,500 g/mol and 25,000 g/mol, more preferably is between about 4,500 g/mol and 16,000 g/mol.
The polyethers can be prepared using conventional reaction conditions well-known to those skilled in the art. Typically, the reaction of compounds according to formula (I) with compounds according to formula (II) or (III) is carried out in the presence of an acid catalyst. Acid catalysts include fluorosulfonic acid and lewis acids such as antimony pentafluoride, boron trifluoride, tin tetrachloride or aluminium trichloride. Suitable reaction temperatures are typically between about 20 and 100xc2x0 C., and more preferably are between about 50 and 90xc2x0 C. The reaction solvent is preferably inert and free of water and include materials like toluene and fluorinated solvents (e.g., trifluorotoluene). After the polyether is prepared, it may be desirable to remove catalyst residues and excess reagents from the reaction mixture. Generally, it is also preferred to replace any fluorinated solvent that is used with another organic solvent that readily solubilises the polyether.
The preferred compounds according to formula (I) contain fluorinated aliphatic groups (Rf) that are preferably stable and inert. Most preferably, such groups are saturated, non-polar, monovalent fluoroalkyl groups, and may, for example be straight chain, branched chain, or cyclic groups or combinations thereof Rf may contain heteroatoms (such as oxygen, divalent or hexavalent sulfur or nitrogen) provided they are bonded only to carbon atoms, and while it is preferably fully-fluorinated, it may contain hydrogen or chlorine atoms as substituents. However, preferably Rf contains no more than one atom of either for every two carbon atoms. Typically, Rf contains at least about 3 carbon atoms, preferably 3 to 14 carbon atoms and more preferably at least 6 carbon atoms. Rf preferably contains about 40% to 80% fluorine by weight, and more preferably, about 50% to 78% fluorine by weight. The terminal portion of the Rf radical is preferably a perfluorinated moiety, preferably containing at least about 7 fluorine atoms, e.g., CF3CF2CF2xe2x80x94, (CF3)2CFxe2x80x94, F5SCF2xe2x80x94. Preferred Rf groups are fully or substantially fluorinated according to the formula CnF2n+1, where n is 3 to 14.
Preferably, s and a in formula (I) are 1 and the organic divalent linking group, L1, is present. Preferably L1 is selected from the group consisting of straight chain, branched chain or cyclic alkylene, arylene, aralkylene, oxy, oxo, thio, sulfonyl, sulfoxy, amino, imino, sulfonamido, carbonamido, carbonyloxy, urethanylene and ureylene groups and combinations thereof such as sulfonamidoalkylene or carbonamidoalkylene. A particularly preferred L1 is represented by the following formula: 
wherein:
R5 represents a lower alkyl containing 1 to 4 carbon atoms,
R4 is selected from the group consisting of linear or branched alkylene groups that contain 1 to 4 carbon atoms, e.g. methylene, ethylene, propylene, butylene, and
p is 0 or 1.
Examples of compounds according to formula (I) are as follows: 
wherein R is a lower alkyl group having 1 to 4 carbon atoms such as methyl and ethyl. 
Compounds of the type 1, 2, 3 and 4 shown in the above list are disclosed in U.S. Pat. No. 4,399,077. Preferred Rf groups in the above formulas are perfluorinated alkyls having 6 to 14 carbon atoms. Still further suitable compounds according to formula (I) are disclosed in U.S. Pat. No. 4,841,090.
The preferred compounds according to formula (II) contain B residues which are linear or branched alkylene groups preferably having about 2 to 4 carbon atoms, alkylene groups substituted with a partially or fully fluorinated aliphatic group optionally linked to the alkylene group through an organic divalent linking group such as a sulfonamido group, and poly(oxyalkylene) groups in which the oxyalkylene moieties preferably have about 2 to 4 carbon atoms. B also can be a divalent linking group according to the following formula: 
wherein:
Rfxe2x80x3 is selected from the group consisting of perfluorinated and partially fluorinated aliphatic groups, and suitable Rfxe2x80x3 groups include the Rf groups described herein;
L3 and L4 each represent organic divalent linking groups which may be the same or different and include those described herein for L1;
R8 is a hydrogen atom or a methyl group;
Z represents the residue of a free radical initiator;
r is a number of 1 to 10;
u is 0 or 1;
w is 0 or 1; and
v is an integer of 1 to 4.
Preferably L3 corresponds to one of the following formulas: 
wherein:
R1 represents a lower alkyl group containing 1 to 4 carbon atoms and R2 is selected from the group consisting of linear and branched alkylene groups that contain 2 to 4 carbon atoms.
A particularly preferred L4 group is xe2x80x94Sxe2x80x94R3xe2x80x94 where R3 is selected from the group consisting of linear and branched alkylene groups having 1 to 4 carbon atoms.
Compounds of formula (II) that include an organic divalent linking group according to formula (A) are typically prepared by oligomerization of a fluorinated ethylenically unsaturated compound (like an acrylate or methacrylate) in the presence of a chain transfer agent containing two functional groups selected from the group consisting of hydroxy, amino or thiol groups. Examples of suitable chain transfer agents include 3-mercapto-1,2-propanediol and 2,3-dimercaptopropanol.
Examples of fluorinated ethylenically unsaturated compounds include the general classes of fluorochemical acrylates, methacrylates, vinyl ethers, allyl compounds containing fluorinated sulfonamido groups, acrylates and methacrylates derived from fluorochemical telomer alcohols, acrylates and methacrylates derived from fluorochemical carboxylic acids, and perfluoroalkyl acrylates and methacrylates as disclosed in EP-A-526 976.
Preferred examples of fluorinated ethylenically unsaturated compounds include: 
where R is a methyl, ethyl or n-butyl group.
The oligomerization is typically carried out using a free-radical initiator. Such free-radical initiators are known in the art and include azo compounds, such as azobisisobutyronitrile (AIBN) and azo-2-cyanovaleric acid and the like, hydroperoxides such as cumene, t-butyl, and t-amyl hydroperoxide, dialkyl peroxides such as di-t-butyl and dicumylperoxide, peroxyesters such as t-butylperbenzoate and di-t-butylperoxy phthalate, diacylperoxides such as benzoyl peroxide and lauroyl peroxide.
Examples of compounds according to formula (II) include: 
where
Rfxe2x80x3 is, for example, a perfluorinated alkyl group containing about 6 to 14 carbon atoms, and preferably about 8 carbon atoms;
alkane diols (particularly C2-C4 alkane diols such as ethylene glycol and 1,4-butanediol);
polyester diols, polycaprolactam diols, poly(oxyalkylene)diols, the fluorochemical diols described in U.S. Pat. No. 4,046,944;
diamines (such as C2-C4 diamines, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,10-diaminodecane, 1,7 diaminoheptane, 1,6-diaminohexane, 1,12-diaminododecane, 1,9-diaminononane, 1,8-diaminooctane, 1,5-diaminopentane, isophoronediamine, Jeffamine(trademark) ED having a molecular weight between 600 and 6000, Jeffamine(trademark) EDR-148, piperazine, 1,8 naphtalenediamine, 1,2/1,3/1,4/phenylenediamine, 4-methyl-1,3-phenylenediamine and 4-methyl-1,2-phenylenediamine);
aminoalcohols (such as 2-aminobenzylalcohol, 4-amino-1-butanol and ethanolamine); and
thiols (such as 1,2-ethanedithiol, 1,3-propanedithiol and 2-mercaptoethanol and polyoxyalkylenethiolen).
Rfxe2x80x2 in formula (III) can be perfluorinated or partially fluorinated. Examples of Rfxe2x80x2 are the same as those described herein for the Rf groups. A compound according to formula (III) can have a single Rfxe2x80x2 group or multiple groups Rfxe2x80x2 and the Rfxe2x80x2 groups can be the same or different. Typically, a compound according to formula (III) has about 1 to 8 Rfxe2x80x2 groups and preferably about 2 to 6.
The linking group, L2, in formula (III) has a valence equal to k+1. Examples of such groups include straight chain, branched chain and cyclic alkylene, arylene, aralkylene, oxy, oxo, thio, sulfonyl, sulfoxy, amino, imino, sulfonamido, carbonamido, carbonyloxy, urethanylene and ureylene groups and combinations thereof such as sulfonamidoalkylene or carbonamidoalkylene. A particularly preferred L2 group is represented by the following formula: 
where R5 is a lower alkyl group containing 1 to 4 carbon atoms and R4 is selected from the group consisting of linear and branched alkylene groups that contain about 2 to 4 carbon atoms, e.g., ethylene, propylene or butylene. More preferably L2 corresponds to the following formula: 
wherein:
L3 represents an organic divalent linking group such as those described above for L1;
L6 represents an organic divalent linking group such as a linear or branched alkylene group (including alkylene groups containing a cyclic group), an arylene group (including a heteroarylene group) or an alkylarylene group;
Z represents the residue of a free radical initiator;
R8 is a hydrogen atom or a methyl group;
k is a number of 1 to 10; and
u is an integer of 0 or 1.
Preferably L3 corresponds to one of the following formulas: 
where R1 is a lower alkyl group containing about 1 to 4 carbon atoms and R2 is a linear or branched alkylene group that contains about 2 to 4 carbon atoms.
Compounds having an L2 according to formula (B) are typically prepared by oligomerization of a fluorinated ethylenically unsaturated compound such as those described above, and in particular an acrylate or methacrylate, in the presence of a functionalized chain transfer agent containing a hydroxy, amino and thiol group. Examples of suitable chain transfer agents include 2-mercaptoethanol, 3-mercapto-2-butanol, 4-hydroxythiophenol, 1-mercapto-2-propanol, 2-mercaptopyridinol, o-, m-, and p-thiocresol and 2-mercaptoethylamine. Preferred compounds include 2-mercaptoethanol, 4-mercaptobutanol, 11-mercaptoundecanol and 2-mercaptoethylamine. The oligomerization is typically carried out using a free radical initiator as described above.
Examples of compounds according to formula (III) include: 
where R is a lower alkyl group that has about 1 to 4 carbon atoms such as methyl, ethyl and n-propyl; 
In the above compounds, Rfxe2x80x2 is preferably a perfluorinated alkyl group containing from about 6 to 14 carbon atoms, and more preferably about 8 carbon atoms, and k is as defined above.
A particularly preferred condensation product for use in the fluorochemical composition is a condensation product of the di- or tri-isocyanate, the polyether and a chain terminator selected from the group consisting of alcohol, thiol and amine compounds. A chain terminator is preferably used in an amount sufficient to react about 5% to 50% of the number of NCO groups of the polyisocyanate, more preferably from about 30% to 50%.
A preferred chain terminator is represented by the following formula (IV):
R6xe2x80x94YH
wherein:
Y is selected from the group consisting of O, S and NR7;
R6 represents an organic radical that is free of active hydrogen atoms and capable of reacting with an isocyanate; and
R7 represents a hydrogen atom or an organic radical that is free of active hydrogen atoms and capable of reacting with an isocyanate, e.g. a lower alkyl group that has 1 to 4 carbon atoms.
Examples of R6 include residues obtained by removing a hydroxyl moiety from an oxime, linear or branched alkyl groups and polyether groups. Another useful chain terminator includes a fluorinated group and can be represented by the following formula (V):
Rfaxe2x80x94L5xe2x80x94
where Rfxe2x80x2 is selected from the group consisting of perfluorinated or partially fluorinated aliphatic groups like those described herein for Rf, and L5 is an organic divalent linking group. Examples of suitable L5 groups include those described herein for L1.
Representative examples of chain terminators include alkanols (such as methanol, ethanol, isopropanol and n-propanol); alkyl ethers of polyethylene glycols (such as polyethyleneglycol methyl ether); fluorinated mono-alcohols such as: xe2x80x83Rfaxe2x80x94CH2xe2x80x94CH2xe2x80x94OH
Rfaxe2x80x94CH(CH3)xe2x80x94CH2xe2x80x94OH
(where R is a lower alkyl group that contains about 1 to 4 carbon atoms (e.g. methyl, ethyl or n-propyl) and Rfa is a perfluorinated alkyl group containing about 6 to 14 carbon atoms, and preferably about 8 carbon atoms); isocyanate blocking agents such as arylalcohols (e.g., phenol, cresols, nitrophenols, o- and p-chlorophenol, naphthols, 4-hydroxybiphenyl); C2 to C8 alkanone oximes (e.g. acetone oxime, butanone oxime); arylthiols (e.g., thiophenol); organic active hydrogen compounds (e.g.; diethyl malonate, acetylacetone, ethyl acetoacetate, ethyl cyanoacetate, epsilon-caprolactam); sodium bisulfite; and hydroxylamine.
A further suitable chain terminator includes a functionalized oligomer that has a functional group selected from the group consisting of hydroxy, amino and thiol groups. Such an oligomer can be prepared by free radical oligomerization of a fluorocherical monomer and/or fluorine free monomer in the presence of a functionalized chain transfer agent as described above. Examples of fluorochemical monomers are those described above. Suitable fluorine-free monomers include the general classes of ethylenic compounds capable of free-radical polymerization, such as, allyl esters (e.g., allyl acetate and allyl heptanoate); alkyl vinyl ethers and alkyl allyl ethers (e.g., cetyl vinyl ether, dodecylvinyl ether, 2-chioroethylvinyl ether and ethylvinyl ether); unsaturated acids (e.g., acrylic acid, methacrylic acid, alpha-chloro acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid and their anhydrides and esters such as vinyl, allyl, methyl, butyl, isobutyl, hexyl, heptyl, 2-ethyl-hexyl, cyclohexyl, lauryl, stearyl, isobornyl and alkoxy ethyl acrylates and methacrylates); alpha-beta unsaturated nitriles (e.g. acrylonitrile, methacrylonitrile, 2-chloroacrylonitrile, 2-cyanoethyl acrylate and alkyl cyanoacrylates); alpha, beta-unsaturated carboxylic acid derivatives (e.g., allyl alcohol, allyl glycolate, acrylamide, methacrylamide, n-diisopropyl acrylamide, diacetoacrylamide, N,N-diethylaminoethylmethacrylate and N-t-butylamino ethyl methacrylate); styrene and its derivatives (e.g., vinyltoluene, alpha-methylstyrene and alpha-cyanomethyl styrene); lower olefinic hydrocarbons which can contain halogen (e.g., ethylene, propylene, isobutene, 3-chloro-1-isobutene, isoprene, and allyl or vinyl halides such as vinyl and vinylidene chloride). Further suitable monomers include urethane-type (meth)acrylates such as a blocked isocyanate obtained by first reacting hydroxyethyl(meth)acrylate with a diisocyanate and subsequently reacting the obtained isocyanate containing (meth)acrylate with an isocyanate blocking agent such as butanone-oxime. The latter type of monomer can be homo-oligomerized or co-oligomerized with for example another (meth)acrylate such as butyl(meth)acrylate.
Suitable di- or tri-isocyanates include aliphatic and aromatic isocyanates and examples of such compounds include: 4,4xe2x80x2-methylenediphenylenediisocyanate, 4,6-di-(trifluoromethyl)-1,3-benzene diisocyanate, 2,4-toluenediisocyanate, 2,6-toluene diisocyaniate, o, m, and p-xylylene diisocyanate, 4,4xe2x80x2-diisocyanatodiphenylether, 3,3xe2x80x2-dichloro-4,4xe2x80x2-diisocyanatodiphenylmethane, 4,5xe2x80x2-diphenyldiisocyanate, 4,4xe2x80x2-diisocyanatodibenzyl, 3,3xe2x80x2-dimethoxy-4,4xe2x80x2-diisocyanatodiphenyl, 3,3xe2x80x2-dimethyl-4,4xe2x80x2-diisocyanatodiphenyl, 2,2xe2x80x2-dichloro-5,5xe2x80x2-dimethoxy-4,4xe2x80x2-diisocyanato diphenyl, 1,3-diisocyanatobenzene, 1,2-naphthylene diisocyanate, 4-chloro-1,2-naphthylene diisocyanate, 1,3-naphthylene diisocyanate, and 1,8-dinitro-2,7-naphthylene diisocyanate; alicyclic diisocyanates such as 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate; 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate; aliphatic diisocyanates such as 1,6-hexamethylenediisocyanate, 2,2,4-trimethyl-1,6-hexamethylenediisocyanate, and 1,2-ethylenediisocyanate; aliphatic triisocyanates such as 1,3,6-hexamethylenetriisocyanate; aromatic tri-isocyanates such as polymethylenepolyphenylisocyanate (PAPI); cyclic diisocyanates such as isophorone diisocyanate (IPDI) and dicyclohexylmethane-4,4xe2x80x2-diisocyanate.
Also useful are isocyanates that contain internal, isocyanate-derived moieties such as biuret-containing tri-isocyanates (e.g., DESMODUR(trademark) N-100, available from Bayer), isocyanurate-containing tri-isocyanates (e.g., IPDI-1890 available from Huls AG, Germany), and azetedinedione-containing diisocyanates (e.g., DESMODUR(trademark) TT available from Bayer). Also suitable are other di- or tri-isocyanates such as DESMODUR(trademark) L and DESMODUR(trademark) W (both available from Bayer), and tri-(4-isocyanatophenyl)-methane (available from Bayer as DESMODUR(trademark) R).
The condensation reaction of the polyether and the isocyanate is carried out under conventional conditions well-known to those skilled in the art. Preferably the reaction is run in the presence of a catalyst. Suitable catalysts include tin salts such as dibutyltin dilaurate, stannous octanoate, stannous oleate, tin dibutyldi-(2-ethyl hexanoate), stannous chloride; and others known to those skilled in the art. The amount of catalyst present will depend on the particular reaction, and thus it is not practical to recite particular preferred concentrations. Generally, however, suitable catalyst concentrations are from about 0.001 to 10 percent, preferably about 0.1 to 5 percent, by weight based on the total weight of the reactants.
The condensation reaction is preferably carried out under dry conditions in a polar solvent such as ethyl acetate, acetone, methyl is,obutyl ketone, and the like. Suitable reaction temperatures will be easily determined by those skilled in the art based on the particular reagents, solvents, and catalysts being used. While it is not practical to enumerate particular temperatures suitable for all situations, generally suitable temperatures are between about room temperature and about 120xc2x0 C.
The fluorochemical composition is soluble in various organic solvents such as ethyl acetate, ethers (di-propylene glycol mono methyl ether, tetrahydrofuran, ethylene glycol ethers), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), alcohols (methanol, ethanol, isopropyl alcohol, glycols), dimethylpyrrolidone and mixtures thereof. Accordingly, the fluorochemical composition can be used as a solution in such organic solvents or alternatively, an emulsion in water of the fluorochemical composition can be prepared according to well-known techniques. For example, a solution of the fluorochemical composition in an organic solvent, e.g., ethyl acetate, gradually can be added to a solution of an emulsifier in water with vigorous stirring. The thus obtained pre-mix may then be subjected to ultrasound treatment or high shear homogenization to obtain a milky to transparent emulsion of the fluorochemical composition in water. If desired, the organic solvent can then be removed e.g. by distillation under reduced pressure.
The fluorochemical composition of this invention can be applied using conventional application method but is peferably used a aqueous emulsion. Alternatively, it can be used as a treatment composition in solvent. An aqueous emulsion will generally contain water, an amount of the fluorochemical composition effective to provide stain release properties to the substrate treated therewith, and a surfactant in an amount effective to stabilize the emulsion. Water is preferably present in an amount of about 70 to 2000 parts by weight per 100 parts by weight of the fluorochemical composition. The surfactant is preferably present in an amount of about 1 to 25 parts by weight, preferably about 2 to 10 parts by weight, per 100 parts by weight of the fluorochemical composition. Conventional cationic, nonionic, anionic, and zwitterionic surfactants are suitable.
The amount of the treating composition applied to a substrate in accordance with this invention is chosen so that the desired stain release properties are imparted to the substrate surface. Typically, the amount of the treating composition is sufficient to provide about 0.01% to 5% by weight, and preferably about 0.05% to 2% by weight, based on the weight of the substrate, of the fluorochemical composition on the treated substrate. The amount of treating composition necessary to impart the desired stain release properties to the substrate can be determined empirically and can be increased as necessary or desired.
To the fluorochemical composition of the invention there may also be added other fluorinated products, polymers or auxiliary products such as starch, dextrin, casein, polyvinyl alcohols, cellulose and cellulose derivatives such as cellulose ethers, copolymers of (meth)acrylic acid and alkyl esters of (meth)acrylic acid, polyglycols such polyethylene glycols, sizing agents, materials to improve water and/or oil repellency, fire proofing or antistatic properties, buffering agents, fungicidal agents, optical bleaching agents, sequestering agents, mineral salts, surface-active agents, or swelling agents to promote penetration.
Particularly suitable auxiliary products for use in the fluorochemical composition include polyvinyl alcohols and non-ionic cellulose ethers. A substantial improvement relative to the release of dirty motor oil stains was noticed for many of fluorochemical compositions of the invention containing polyvinyl alcohol or a non-ionic cellulose ether, whereas the improvement was less pronounced for the release of tea or wine stains. This finding is rather surprising since the addition of other hydrophilic polymers such as polyglycols or copolymers of alkyl (meth)acrylate and (meth)acrylic acid to the fluorochemical composition did not show this improvement or even lead to a reduced stain release performance of the fluorochemical composition. Preferred polyvinyl alcohols are those having a degree of hydrolysis of at least about 65% by weight, and more preferably a degree of hydrolysis of at least about 85% by weight. Most preferably, the polyvinyl alcohol has a degree of hydrolysis between about 65 and 90% by weight.
Examples of non-ionic cellulose ether derivatives include methyl cellulose, hydroxypropyl cellulose and methylhydroxypropyl cellulose. Particularly preferred cellulose ethers are hydroxyalkyl cellulose ethers. Preferably the etherified cellulose is highly hydrophilic. Accordingly, cellulose ethers that contain large hydrophobic substituents such as the hydrophobically modified cellulose ether NEXTON(trademark) (available from Aqualon) are not preferred for use in the fluorochemical composition of this invention.
The substrates treated by the fluorochemical composition of this invention are not especially limited and include plastic, metal, glass, fibrous materials such as textile fabrics, wood, non-wovens and paper. The fluorochemical composition is particularly useful for imparting stain release properties to a substrate that comprises natural fibers, in particular a substrate that consists of cellulose fibers or a substrate consisting of cellulose and polyester fibers. Substrates treated with a fluorochemical composition of this invention have particular good stain release properties for dirty motor oil stains and tea stains.
In order to affect treatment of a textile substrate, the substrate can be immersed in a diluted emulsion. The saturated substrate can then be run through a padder/roller to remove excess emulsion, dried and cured in an oven at a temperature and for a time sufficient to provide a cured treated substrate. This curing process is typically carried out at temperatures between about 50xc2x0 C. and 190xc2x0 C. depending on the particular system or application method used. In general, a temperature of about 120xc2x0 C. to 170xc2x0 C., preferably about 150xc2x0 C. to 170xc2x0 C. for a period of about 20 seconds to 10 minutes, preferably 3 to 5 minutes, is suitable. The cured treated substrate can be used as desired, e.g., incorporated or fashioned into a garment.
The invention is further illustrated by reference to the following examples without however the intention to limit the invention thereto.